SMC91C95 Ver la hoja de datos (PDF) - SMSC -> Microchip

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SMC91C95

ISA/PCMCIA Full Duplex Single-Chip Ethernet and Modem Controller with RAM

SMSC -> Microchip 

PACKET FORMAT IN BUFFER MEMORY

The packet format in memory is similar for the

TRANSMIT and RECEIVE areas. The first

word is reserved for the status word, the next

RAM

OFFSET

bit15

(DECIMAL)

word is used to specify the total number of

bytes, and that in turn is followed by the data

area. The data area holds the packet itself, and

its length is determined by the byte count. The

packet memory format is word oriented.

bit0

0

S TAT U S W O R D

2

RESERVED

BYTE COUNT (always even)

4

DATA AREA

1536 Max

CONTROL BYTE

LAST DATA BYTE (if odd)

FIGURE 8 - DATA PACKET FORMAT

STATUS WORD

BYTE COUNT

DATA AREA

CONTROL BYTE

TRANSMIT PACKET

Written by CSMA upon transmit

completion (see Status

Register).

Written by CPU.

Written by CPU.

Written by CPU to control

ODD/EVEN data bytes.

RECEIVE PACKET

Written by CSMA upon receive

completion (see RX Frame

Status Word).

Written by CSMA.

Written by CSMA.

Written by CSMA. Also has

ODD/EVEN bit.

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